A teenager accused of raping and killing a 47 year-old Dereham grandmother denied he stabbed the woman and claimed she had agreed to have sex with him.

A teenager accused of raping and killing a 47 year-old Dereham grandmother denied he stabbed the woman and claimed she had agreed to have sex with him.

The defendant - who was 16 at the time and cannot be named by order of the court - has denied the rape and murder of Elaine Walpole at her flat at Dreibholz Court, off Norwich Road, Dereham, in April. He also denies affray in Dereham.

Giving evidence at Norwich Crown Court the teenager, who is now 17, admitted he had sex with Ms Wapole but said that she had consented.

Asked if he had stabbed her in the neck he replied: “No” and added that he did not know who had stabbed her.

He told the jury that he was born in West Africa and had come to Dereham after his mother married a man she met in Gambia.

He obtained a visa to come to stay with his mother and step-father in July 2007.

The teenager said at first he got on well with his step-father but said that problems developed as he did not like him playing his music too loud and thought he should get a job.

Earlier jurors were shown a blood-stained kitchen knife and told it had DNA on it of the defendant.

Dr Peter Hau said the knife had blood on it and DNA came from Ms Walpole and the youth.

A pair of boxer shorts recovered from Ms Walpole's living room had the teenager's DNA on them as well as that of Ms Walpole.

The court has heard that when he was arrested on suspicion of affray, the youth had no underpants on.

A spot of blood found on the undersole of a left boot was that of Ms Walpole, having come into contact with her wet blood.

Dr Hau said one of his conclusions was that that youth had recent sexual intercourse with Ms Walpole.

Under cross examination from the youth's barrister Alison Levitt, QC, Dr Hau said he had no knowledge of the time of Ms Walpole's death.

She was last seen alive on April 26 and was found dead three days later with her throat cut.

A close friend and neighbour, Michael Goldsach, said he last saw Ms Walpole walking outside his flat with a dark-skinned young man but after that she failed to answer any of his mobile phone calls.

After three days he phoned 999 as he thought she might have fallen over and injured herself after she had been drinking and said he was “very shocked” when her half-naked body was discovered lying in her flat.

On Thursday the court heard how the drunken defendant had sparked off mayhem in Dereham town centre after he allegedly raped and murdered Ms Walpole.

The youth tried to chat up a woman, became involved in an altercation with her boyfriend and other men, ran out of a supermarket waving a bottle and had to be dragged to the ground in the Market Place before being arrested.

The incidents happened on the evening of April 26, the same day he is accused of killing her.